Cold Acclimation Green Crab Experiment Part 8

Temperature tweaks and setting up the cold room


On Friday Nate added some extra rack lighting! Excellent for visibility and ensuring even lighting throughout, but I noticed that my 0ºC test tanks were getting a bit warmer, possibily because of the extra heat being generated by the new bulbs. I kept the set up over the weekend and checked on temperatures Monday.

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Figures 1-2. Temperatures of middle and bottom rack

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Figures 3-6. Temperature of 0ºC tanks

The middle rack is MUCH warmer that it used to be, while the bottom rack is staying constant. I decided to move my 0ºC test tanks down to the bottom rack for an extra day to see if that returns the tank to their cooler temperature. I could also move the tanks directly to the floor and they would get the lighting from the bottom rack if that helps maintain temperature. My guess is just moving to the bottom rack will allow for cooler air flow without any lighting fixtures under the tank, since the bottom rack HOBO logger stayed cool. I could then use the middle rack for the 5ºC tanks, and the heaters won’t have to work as hard!

Interestingly, there’s a 1ºC discrepancy in the temperature of my 0ºC tanks. I’m not sure why that is…but hopefully being on the bottom rank will smooth that out as well. I’m sure keeping four tanks next to eachother instead of two with some space will also keep temperature a bit more constant. I could also probably crank the room down a bit without any negative impacts. And, that’s the point of doing the MA experiment first! To figure out all the little things before the WA run.

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Figures 7-10. Temperature of 5ºC tanks

Apart from the blip in one of the tanks because the air stone got disloged and water wasn’t circulating well, temperature looks good and decently consistent between tanks!


I checked the 0ºC tanks this morning and they were at 1ºC instead of 0.5ºC!

Figures 11-14. Temperature of 0ºC tanks

I was puzzled since I moved them down a rack explicitly to see if I could get more airflow. After pacing in the cold room, I realized the back of the cold room is cooler than the front, even in the back half of the room. I also noticed that the second 0ºC tank had a dislodged airstone so it wasn’t mixing well. I decided to shake things up by moving the two 0ºC tanks to the right side of the room which felt like it got more direct fan. And it worked! I forgot to save the screenshots but those tanks had cooled down to ~0.5ºC.

My plan for today is to set up the cold room, with the 5ºC tanks on the left (aka the racks with more lights and heating) and the 0ºC tanks on the right (where things are cooler).

With Catlin and McCaela’s help, I did the following:

  • Calibrate and rename 16 to match with tanks
  • Obtain four more tanks and fill with seawater
  • Label tanks 1-8
  • Add velcro and mesh to all the tanks
  • Add airstones to all tanks
  • Remove heaters from existing tanks
  • Add nitrogen filters to all tanks
  • Clean tanks with seawater and top off with more seawater
  • Add timers to the lights

Going forward

  1. Calibrate HOBO loggers
  2. Create labels and label tubes
  3. Set up cold room
  4. Obtain MA crabs!
  5. Tailor PCR protocol for new primers
  6. Develop restriction band digest for genotyping
  7. Develop heart rate protocol
Written on June 4, 2024